Breakthrough Reading Fingerprints Even After They Are Gone

Researchers at Leicester have just announced the development of a fingerprint visualization technique that allows for reading a fingerprint even after the print itself has been removed. This new method promises the possible solution of even decade-old unsolved cases.

Forensic scientists at Leicester University's Forensic Research Center have been working with the Northamptonshire police department in England to develop a new method that enables scientists to "visualize fingerprints" even after the print itself has been removed. The technique is specifically for fingerprints on metal objects such as guns, cartridges, cartridge cases, and knives.

"For the first time we can get prints from people who have handled a cartridge case before it was fired," said Dr. John Bond, honorary fellow at Leicester University and scientific support manager at the Northamptonshire police department. The procedure works by applying an electric charge to a metal object—say, a gun or fired cartridge case—which has been coated with a fine-grain conducting powder, similar to that used in photocopiers. Even if the print has been washed off, it leaves a slight corrosion on the metal, and this attracts the powder when the charge is applied, revealing a residual fingerprint. Even if heat from the discharge of a firearm vaporizes a fingerprint, the residual corrosion can allow it to not only be located but also restored, according to Bond.

As a result of the research, cases dating back decades could be reopened because the underlying print never disappears. Bond believes that only abrasive cleaning in which the outer layer of metal is removed can prevent the technique from working. Dr. Bond and Professor Rob Hillman of the chemistry department at the university now intend to take the research forward via a three-year Ph.D. studentship that will commence next year.

This breakthrough is particularly exciting, given the historically low rate of recovery of even the most limited fingerprint-ridge detail on firearms and fired cartridge cases. It is conceivable that this could have an effect similar to that of DNA technology in solving old crimes where no fingerprints were originally found.